The invention relates to a dental x-ray diagnostic apparatus having a unit which can be rotated about vertical axes, essentially comprising an x-ray tube and a film carrier, and having a head support arranged therebetween for the support of the patient's head, said head support being adjustably arranged in a horizontal plane vis-a-vis its mounting in order to provide the possibility of locating the head in various positions for different object exposures.
In order to do justice to various exposure techniques in the mandible region of a patient in dental x-ray diagnostics; for example, in order to make exposures of the quadrant tooth sector, of the sinus cavities, the mandible joints or ear passages, it is necessary to adjust a head support, which can be outfitted with a chin support, a bite block or with a front tooth support, to various positions, at least in the horizontal plane.
In known dental x-ray diagnostic apparatus a pointer is attached at the head support, which is adjustably attached on a guide rail, which pointer cooperates with a line scale arranged on the mounting. The respectively adjusted position of the head support can be read on the line scale.
With the adjustment of the various positions it can easily happen that the pointer is accidentally set for a wrong scale value, and thereby the head support is not adjusted in the respective position for the desired exposure. Moreover, the searching for the respective scale value for a desired exposure is relatively time-consuming.